Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Knowing where the reservoir is located and the type of geological formation containing the reservoir is valuable in determining where to drill and in deciding how to efficiently produce the reservoir. One method of mapping the area around a borehole uses an acoustic source to produce acoustic source signals and acoustic receivers to receive the acoustic source signals. As the acoustic signals travel through the geological formations, their profiles are altered and then received by the acoustic receivers. By processing the waveforms and acoustic signals detected by the receivers, a representative indication of the location, composition, and extent of various geological formations may be obtained. As petroleum exploration occurs in deeper wells and in more complex sub-surface formations, more powerful air-gun sources have been deployed to deliver acceptable seismic signal quality. The larger air-gun sources can produce substantial shock loads on the hull of a seismic vessel.